May 31: Chancellor Angela Merkel was forced to fly around in circles and miss a one-on-one with Prime Minister Manmohan Singh today after Iran closed its airspace to the plane ferrying the German leader to New Delhi.

The blockade set off a diplomatic row and mid-air negotiations during which the German equivalent to Air Force One circled over Turkey for about two hours on its first international flight after a revamp.

Im very glad I arrived here safely in India, Merkel, who apparently slept like a log through the drama, later told a news conference with Singh in the Indian capital.

German government spokesperson Steffen Seibert called the Iranian move a violation of normal diplomatic privilege that Merkel had never experienced before.

The Iranians blamed an unexplained technical problem. One theory is that Iran has been eager to punish the chancellor for closing down the European-Iranian Trading Bank in Hamburg after the US complained that it was breaking sanctions by funnelling payments from India for Iranian oil.

Germany summoned the Iranian ambassador in Berlin to protest the breach of international protocol, said foreign minister Guido Westerwelle. Irans move to hinder the chancellors trip is absolutely unacceptable, he said. This is lack of respect for Germany that we wont accept, said Westerwelle.

Iran had granted overflight permission to Merkels plane before it left Berlin but that was revoked after the chancellor was airborne, said the German governments media office. Strange start to Indian trip — Iran temporarily denies overflight to chancellors plane. Delayed landing in Delhi, Seibert tweeted.

A second plane carrying several of Merkels ministers had no trouble transiting Iranian airspace.

Iranian foreign ministry spokesperson Ramin Mehmanparast later said: The delay in giving clearance to her flight was only due to a technical problem which was resolved quickly and the flight was able to continue its journey.

Christoph Heusgen, Merkels security and foreign policy adviser, led negotiations with Iran from aboard Merkels plane and it was eventually allowed to fly over Iran.

Getting the permission involved intense diplomatic interventions in Berlin and Tehran, a German official said. The reason for the temporary refusal to pass through the airspace is still unknown, said the official.

The pilots negotiated for 20 minutes with air traffic control but then the Iranians refused to talk and the plane was forced to stay circling over Turkey and apply again for clearance. Nico Fried, of the German newspaper Suddeutsche Zeitung, said: The circling continued for two hours. Sometimes we would see the dawn breaking on the left of the plane, sometimes on the right.

According to one reporter, Merkel slept like a log and missed all the action.

The incident unfolded at a time Iranian officials are in talks with their Indian counterparts to try to resolve an impasse over payments for oil sales worth about $12 billion a year.

Earlier this year, Germany allowed India to pay for the oil via the Hamburg-based bank that handles international trade for Iranian companies. But India halted that conduit in April after discussions with Merkel, and the bank has since been put under EU sanctions.

Germany is part of the group of six nations negotiating with Iran over its nuclear programme. The government in Berlin also supports sanctions against Iran. Iran is suspected of covertly developing nuclear weapons, but it denies that.

The flight marked Merkels first official trip aboard her newly revamped government Airbus A340 Konrad Adenauer, Germanys equivalent of the US Air Force One.

It was supposed to be a big occasion not only because Germany and India were on the verge of clinching important trade deals, but also because the flight had been billed as the most comfortable ever journey with the chancellor.

Until now, accompanying the German leader has been a spartan affair on battered East German planes. The chancellor has been stranded several times — in Algeria, the President had lent her his plane so that she could fly home.

The circling had its ripple effect in Delhi. Merkel and Singh were scheduled to meet at 10.30am for a restricted or a one-on-one meeting. The two leaders share a good rapport — while Singh today said he had always admired her leadership qualities, Merkel had recently said that of all the G20 leaders, she preferred talking to him.

However, the Germans could land in Delhi only at 10.30am, instead of 8.30am as scheduled, because of the mid-air diversion. By the time Merkel reached Delhis Hyderabad House — the venue of the talks — it was well past the time slot kept aside for the meeting with Singh.

In order to protect the rest of the schedule, they dispensed with the tete-a-tete, and delegation-level talks started. Merkel flies out to Southeast Asia early tomorrow morning. Sources said Singh and Merkel did catch up at a private dinner that the Prime Minister hosted for the chancellor at his residence.